General comment:

The manuscript shows the development and analysis of an air quality management system to help air quality policies and management in Brazil. The paper brings a very interesting topic, specfically due to: i) the current lack of numerical simulated dataset needed to work with air quality in Brazil; ii) Not everyone that works with meteorological and/or air quality in knows how to produce and work with atmospheric models. Thus, having the possibility to use a platform, as proposed by the authors for a specific region, is an indubitable advantage. I would recommend the paper for publishing after addressing all the following comments.

My major concern is on creating numerical simulation for a country with such a large size as Brazil. For that, a massive statistic evaluation is mandatory and not only in cities with large amount of pollutants emissions but also in background regions, such as the Northwest of the Amazonas state (near to the Amazon Tall Tower Observatory -ATTO). In cases where a monitoring network is not available, the authors should use remote sensing to evaluate the numerical experiments. There is a good amount of satellite products to use in this case: MODIS to evaluate AOD; TROPOMI to evaluate NO2 and HCHO; IASI+GOME2 to evaluate O3 (on the 20km grid). If the authors are proposing to make available numerical simulations for the entire country, it requires evaluation for the whole domain or at least an evaluation scale where it shows a confiability level of the data. In order to assume the premises of good modeling results for regions without validation, the authors need to build an underlying analysis by showing how the model performs on key scenarios, such as:

i) Background regions.

ii) Under anthropogenic emission effects (also analyze the model’s abilities with plume transport).

ii) Long range transport (specially in the Amazon region during the wet season with (between January and May), when the Intertropical Convergence Zone (ITCZ) is more intense in the south, allowing the long transport of BC (biomass burning emissions) and dust from Africa (Sahara desert) (Artaxo et al., 2013; Martin et al., 2016; Pöhlker et al., 2018, 2019). With the availability of several years of BC background measurements at the ATTO tower, the authors could separate African episodic events from the rather constant regional BC concentrations that are relevant when comparing with modeled values not under anthropogenic influence.

Once it is shown that the model is capable of representing key scenarios, the idea of using modeling data for regions not fully evaluated is more reasonable. 

Specific comments:

• I would strongly recommend the authors to put more focus on the states with the most extensive networks of AQS such as SP, RJ and MG, in addition of course to PR, SC and RS (I am suspicious it was done that way because the authors are based in SC).
• The authors should have a modeling strategy component focused on the States with AQS to allow the increase of the spatial resolution, and thus, get a more robust statistical evaluation for medium and small-sized cities that, otherwise, would not be properly covered by coarse resolution model simulations (10 km or more). I also recommend the authors to do a full evaluation by selecting a region with AQS available and combine observational data from satellites and field campaigns (if available). The idea here is to try to have a case where the model can be massive evaluated vertically and horizontally. 
• If there is no observations to compare with in States other than those with AQS, I do not think a country-scale simulation is really worthwhile here. Maybe the authors should provide a strategy/approach for validade/evaluate regions without AQS (remote sensing?).
• As most of the air quality stations used for model evaluation are placed in southeastern Brazil, why not focusing on the largest metropolitan areas of the country, such as, the metropolitan areas of São Paulo, Rio de janeiro, Belo horizonte, etc?. Or maybe use passed campaigns such as The Green Ocean Amazon experiment (GoAmazon2014/5) or The Regional Carbon Balance in Amazonia (BARCA) to evaluate the chemistry component of the model in different vertical levels and with high spatial resolution.
• If 2019 is just a sampling year, what is the base period? 
• The authors claimed that, currently available initiatives including reanalysis and satellite products are still not  providing datasets with large spatial and temporal resolutions for developing air pollution policies in Brazil. In the biomass emission perspective, have the authors checked the fire products from Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Suomi NPP satellite - VIIRS (375 m resolution for fire activities). The paper Ferrada et al., 2022 (Introducing the VIIRS-based Fire Emission Inventory version 0 (VFEIv0)) shows a new open biomass burning inventory that relies on the fire radiative power (FRP) data from VIIRS.
• BRAVES uses activity data from field campaigns conducted in the metropolitan area of São Paulo. It really does not make any sense take this region out of a very high-resolution simulation design. 
• NCAR (FINN) version 1.5 (Wiedinmyer et al., 2011). This version is pretty outdated. An updated version is now available https://egusphere.copernicus.org/preprints/2023/egusphere-2023-124/egusphere-2023-124.pdf.
• The authors mentioned that he WRF model demonstrated the ability to reproduce diurnal and seasonal variability of winds in the Brazilian North-East region (Souza et al., 2022a). Although, this resolution is slightly lower than the one used in this work for the parent domain. If wouldn't be better to just focus on the largest metropolitan areas of Brazil?. I am assuming that you have set up the model simulations at 20 km resolution in an attempt to avoid out-of-memory and space of storage issues, but if that is the case, why not just focusing on high densely areas?
• The authors mentioned that the lack of data quality assurance may compromise the credibility of the available air quality observations in Brazil. It is true, and consequently, this could potentially compromise any analysis conducted on these data sets. In my view, a modeling study that centers on the States with the most extensive networks of AQS would have had a more effective simulation strategy, as the one mentioned in the previous comments. This point also brings the importance of using data from previous campaigns with high quality assurance. 

References: 

Artaxo, P., Rizzo, L. V., Brito, J. F., Barbosa, H. M., Arana, A., Sena, E. T., Cirino, G. G., Bastos, W., Martin, S. T., and Andreae, M. O.: Atmospheric aerosols in Amazonia and land use change: from natural biogenic to biomass burning conditions, Faraday Discuss., 165, 203–235, https://doi.org/10.1039/C3FD00052D, 2013.

Martin, S. T., Artaxo, P., Machado, L. A. T., Manzi, A. O., Souza, R. A. F., Schumacher, C., Wang, J., Andreae, M. O., Barbosa, H. M. J., Fan, J., Fisch, G., Goldstein, A. H., Guenther, A., Jimenez, J. L., Pöschl, U., Silva Dias, M. A., Smith, J. N., andWendisch, M.: Introduction: Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5), Atmos. Chem. Phys., 16, 4785– 4797, https://doi.org/10.5194/acp-16-4785-2016, 2016.

Pöhlker, C., Walter, D., Paulsen, H., Könemann, T., Rodríguez- Caballero, E., Moran-Zuloaga, D., Brito, J., Carbone, S., De- grendele, C., Després, V. R., Ditas, F., Holanda, B. A., Kaiser, J. W., Lammel, G., Lavriˇc, J. V., Ming, J., Pickersgill, D., Pöh- lker, M. L., Praß, M., Löbs, N., Saturno, J., Sörgel, M., Wang, Q., Weber, B., Wolff, S., Artaxo, P., Pöschl, U., and Andreae, M. O.: Land cover and its transformation in the backward trajec- tory footprint region of the Amazon Tall Tower Observatory, At- mos. Chem. Phys., 19, 8425–8470, https://doi.org/10.5194/acp- 19-8425-2019, 2019.

Pöhlker, M. L., Ditas, F., Saturno, J., Klimach, T., Hrabˇe de Ange- lis, I., Araùjo, A. C., Brito, J., Carbone, S., Cheng, Y., Chi, X., Ditz, R., Gunthe, S. S., Holanda, B. A., Kandler, K., Kesselmeier, J., Könemann, T., Krüger, O. O., Lavriˇc, J. V., Martin, S. T., Mikhailov, E., Moran-Zuloaga, D., Rizzo, L. V., Rose, D., Su, H., Thalman, R., Walter, D., Wang, J., Wolff, S., Barbosa, H. M. J., Artaxo, P., Andreae, M. O., Pöschl, U., and Pöh- lker, C.: Long-term observations of cloud condensation nuclei over the Amazon rain forest – Part 2: Variability and charac- teristics of biomass burning, long-range transport, and pristine rain forest aerosols, Atmos. Chem. Phys., 18, 10289–10331, https://doi.org/10.5194/acp-18-10289-2018, 2018.

General comment:

The current paper aims to develop an emission database for the entire country of Brazil based on local emissions inventories for industries, vehicular emissions estimations, MEGAN for biogenic emissions, and FINN for fire emissions. Additionally, the authors aim to make this dataset available to the community.

The initiative is really good not only for Brazil but also for South America. The countries inside South America have their connection and impact of long-range transport of pollutants. Thus, an emissions inventory for the largest country is appreciated. Primarily when the government and environmental protection agencies do not provide the official data for the community

The authors have put much effort into the work, gathering all data (meteorology, emissions, temporal profile, chemical profile, different models, different databases), processing the models, and performing the air quality modeling..

The database is interesting and valuable for Brazil and South America and will be very appreciated by the community. As mentioned by the authors, the lack of this information holds the improvement in the air quality across Brazil. I would recommend the paper for publishing after addressing the following comments.

1. Introduction

The introduction shows the situation of the region of study regarding air quality problems, fire emissions, countryside problems with air pollution, and vehicle emissions across the country, among others. Additionally, the authors exposed the lack of air quality monitoring stations and emissions inventory. This situation is a concern for any country since the lack of this information is critical for air quality management.

The authors stated: “Currently, available initiatives, including reanalysis and satellite products, are still not providing datasets with large spatial and temporal resolutions for developing air pollution policies in Brazil.” I would like some publications to enforce this statement. There are ERA reanalysis data with one hour of time resolution and less than 10km of spatial resolution. Additionally, there are MODIS data for air quality, probably not hourly, but there is a frequency that may help.

2 BRAIN Database

Error in the Figure 1 b): “Annual Indutrial”

2.1.1 Vehicular emissions

The BRAVES model was used to estimate the vehicle emissions. The database was validated in another paper, but I would like to see some explanation on how the authors estimated the activity data, especially over countryside cities. This information is crucial for understanding vehicular emissions.

2.1.2 Industrial emissions

It used the emissions inventory of Espírito Santo, Minas Gerais, and Santa Catarina, which are local emissions inventory provided by the Environmental Protection Agency. Additionally, the emissions inventory developed by  Kawashima et al. (2020) was also used. These emissions inventories are not from the same year and do not cover the entire state. Did the authors scale the emissions for the current modeling year, which is 2019? Please explain this in the text.

Additionally, have the authors considered applying EDGAR emissions across the regions without emissions inventory, especially for the industry sector?

2.1.3 Biomass burning emissions

FINN is a good database for biomass burning, primarily for providing daily Biomass burning emissions. I noticed the authors used the FINN 1.5, but the FINN version 2.5 is available. I recommend the authors to use the updated version.

2.1.5 Sea spray aerosol emissions

The Sea spray aerosol is handled inline in CMAQ. Is there a way to extract these values to use in another photochemical model, such as WRF-CHEM or CAMx?

2.3 Air Quality & 2.3.1 Models’ performance

The air quality was developed using CMAQ v5.3.2. The boundary conditions for the Brazilian domain are based on the standard profile. I would recommend that the authors provide Boundary conditions from a global model, such as GEOS-Chem, as mentioned in the paper, in this version or future work. This will account for the long-range transport of air pollutants across the country.

Regarding the model performance. The lack of air quality monitoring stations across Brazil was mentioned. However, there are some important areas in which the model should be validated for at least a few days across the modeling scenarios. This helps to understand if the emissions inventory should increase or decrease the total emissions. A validation with satellite data will improve this analysis.

Additionally, there is only the validation and plot for the 20x20km. How did the 4x4km modeling domain perform? I recommend adding this information to the text and supplementary material.