RESUMO
The promulgation and implementation of the national and Beijing municipal standards for air pollutants emitted from crematoriums has effectively alleviated the problem of "black smoke" in crematoriums, but noticeable odor in crematoriums remains. We determined the level of odor emissions in crematoriums by monitoring the odor concentrations of cremators, incinerators, and cremation workshops in five crematoriums in Beijing. Subsequently, we analyzed the major contributing factors to the odor level and proposed control measures. A high odor concentration in crematoriums was observed; two different mechanisms were proposed to explain this finding. First, poor ventilation conditions in workshops and inadequate airtightness of equipment resulted in dimensionless concentrations of unorganized odor emissions in the workshops ranging from 97 to 732, with an average of 504, which is much higher than the standard level of 20. Second, the postprocessing facilities used in cremation sites produce poor odor removal, which, coupled with fuel usage and unregulated operations, led to high concentrations of organized odor emissions ranging from 231 to 1303 (910 on average) for cremators and incinerators. The odor emissions of cremators and incinerators meet the Integrated Emission Standards of Air Pollutants (DB11-501-2017), which are suitable for industries containing industrial kilns but not for crematoriums. The odor emissions in crematoriums are lower than those emitted from industries, such as fiber manufacturing and activated carbon processing. However, the unique geographical locations of crematoriums, high population density, and high exposure risk to local residents necessitate strengthening the management and control of odor emissions from crematoriums. To further address the problem of odor emissions from crematoriums in Beijing, further clarification and tightening of industry standards for the concentration limits of organized and unorganized odor emissions is recommended. Crematoriums will thus be prompted to increase odor control in workshops and adopt and improve deodorization facilities, including the installation and application of treatment facilities, such as adsorption and biological control.
RESUMO
According to the traffic flow variation from January 2019 to August 2020, emissions of primary air pollutants from highway vehicles were calculated based on the emission factor method, which integrated the actual structure of on-road vehicles. The characteristics of on-highway traffic flow and pollution emissions were compared during various progression stages of coronavirus disease (COVID-19). The results showed that the average daily traffic volume decreased by 38.2% in 2020, with a decrease of 62% during the strict lockdown due to the impact of COVID-19. The daily emissions of primary atmospheric pollutants decreased by 29.2% in 2020 compared to the same period in 2019. As for the structure of on-highway vehicle types, the small and medium-sized passenger vehicles predominated, which accounted for 76.3% of traffic, while trucks and large passenger vehicles accounted for 19.7% and 4.0%, but contributed 58.4% and 33.9% of nitrogen oxide (NOx) emissions, respectively. According to the simulation results of the ADMS model, the average concentrations of NOx were reduced by 12.0 µg/m3 compared with the same period in 2019. As for the implication for future pollution control, it is necessary to further optimize the structure of on-highway and the road traffic vehicle types and increase the proportions of new-energy vehicles and vehicles with high emission standards.