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Luo et al. Carbon Footprints 2025, 4, 14 https://dx.doi.org/10.20517/cf.2024.53 Page 7 of 24

Table 1. Basic information of ground meteorological observation stations in Shanghai
Name Station ID X (km) Y (km) Observation site elevation (m)
Minhang 58361 344.16 3,442.17 5.5
Baoshan 58362 352.12 3,473.96 5.5
Jiading 58365 332.97 3,471.03 4.4
Chongming 58366 357.11 3,504.45 4.3
Xujiahui 58367 350.56 3,451.95 4.6
Nanhui 58369 384.38 3,436.49 5
Pudong 58370 360 3,456.02 4.4
Jinshan 58460 342.03 3,400.84 5.2
Qingpu 58461 320.97 3,445.99 4
Songjiang 58462 331.42 3,435.02 4.2
Fengxian 58463 356.19 3,418.08 4.6

Table 2. Road traffic emission data for Baoshan district
Field name Explanation
Road ID Unique identifier with no inherent meaning
Date Format: “YY-MM-DD”
Time Time unit: 1 h
Vehicle type 0: Total; 11: Taxi; 21: Bus; 31: Shanghai-plated small passenger car; 32: Out-of-province small passenger car; 33: Shanghai C-
plated small passenger car; 41: Small truck; 51: Large bus; 61: Large truck; 71: Container truck
Road length Unit: kilometers
Average vehicle Average speed of all vehicle types passing through the road per hour, unit: kilometers/hour
speed
Traffic flow Number of vehicles passing through the road per hour, unit: vehicles/hour
Vehicle mileage Total vehicle mileage per hour, unit: vehicle kilometers/hour
NO emissions Total NO emissions from all vehicle types per hour, unit: grams/hour
x x

estimated based on NO data. According to the Technical Guidelines for Environmental Impact Assessment
x
- Atmospheric Environment, issued by the Ministry of Ecology and Environment of China, a conversion
rate of 90% for NO /NO should be used when calculating hourly or daily mass concentrations of NO . For
2
2
x
annual average mass concentrations, an estimated conversion rate of 75% is recommended . However, this
[37]
standardized approach may constrain the flexibility of air pollution simulations, potentially leading to
inaccurate assessments of ambient air quality. To improve this, Luo et al. proposed a proportional
simulation method for converting NO to hourly NO concentrations . This method derives the NO /NO
[38]
x
2
2
x
conversion rate from hourly concentration data collected at meteorological observation stations. Results
show that it more accurately and reasonably simulates the dispersion and transport of NO .
2
In this study, NO concentrations are derived using an hourly NO /NO conversion rate. The data used to
2
x
2
calculate the conversion rates were obtained from traffic monitoring stations in Shanghai, as shown in
Table 3. These include five roadside air monitoring stations, one airport station, and two port stations,
covering the period from 00:00 on November 11 to 23:00 on November 30, 2019. The five roadside
monitoring stations are located within the Outer Ring Road, while the airport and port stations are also
situated nearby.
The conversion rate calculation formula is as follows, where i represents the hour, NO is the NO
2i
2
concentration at hour i, and NO is the NO concentration at hour i:
X
Xi
Conversion Rate i = NO /NO (1)
Xi
2i