Table 3.

Effects of activity restrictions and meteorology on air quality; predicting air quality during the month of March (2015–2020); measurements from São Paulo, Los Angeles, New York and Paris networks ^1,2.

Dep. (unit)	CO (ppm)	O3 (µg/m3)	NO2 (µg/m3)	PM2.5 (µg/m3)
São Paulo
Coronavirus scenario
Activity restriction (a) 3	0.11 ± 0.001 *	−10.95 ± 0.002 *	4.00 ± 0.001 *	0.54 ± 0.000 *
Meteorological factors
T (°C)	0.03 ± 0.000 *	3.49 ± 0.001 *	1.18 ± 0.000 *	0.74 ± 0.000 *
RH (%)	0.01 ± 0.000 *	−0.59 ± 0.000 *	−0.01 ± 0.000 *	−0.17 ± 0.000 *
WS (m/s)	−0.19 ± 0.001 *	0.66 ± 0.002 *	−10.40 ± 0.003 *	−5.49 ± 0.001 *
Specific regressions
R2	0.64	0.50	0.45	0.53
Dep.	0.54	36.40	30.25	13.62
Los Angeles
Coronavirus scenario
Activity restriction (a) 3	0.09 ± 0.001 *	2.52 ± 0.02 *	11.01 ± 0.36 *	2.99 ± 0.001 *
Meteorological factors
T (°C)	0.001 ± 0.000 *	2.54 ± 0.02 *	1.22 ± 0.000 *	0.66 ± 0.001 *
RH (%)	−0.003 ± 0.000 *	−0.05 ± 0.001 *	−0.33 ± 0.000 *	0.10 ± 0.000 *
WS (m/s)	−0.09 ± 0.001 *	0.08 ± 0.01 *	−8.31 ± 0.001 *	−1.66 ± 0.001 *
Specific regressions
R2	0.58	0.25	0.55	0.37
Dep.	0.30	87.33	29.68	9.13
New York
Coronavirus scenario
Activity restriction (a) 3	0.11 ± 0.001 *	−7.96 ± 0.91 *	14.18 ± 0.004 *	2.03 ± 0.001 *
Meteorological factors
T (°C)	0.004 ± 0.000 *	−0.01 ± 0.07	0.39 ± 0.001 *	0.12 ± 0.000 *
RH (%)	0.002 ± 0.000 *	−0.34 ± 0.02 *	0.20 ± 0.000 *	0.03 ± 0.000 *
WS (m/s)	−0.016 ± 0.000 *	3.22 ± 0.23 *	−3.38 ± 0.001 *	−0.23 ± 0.000 *
Specific regressions
R2	0.23	0.32	0.23	0.14
Dep.	0.30	54.68	34.45	6.96
Paris
Coronavirus scenario
Activity restriction (a) 3	0.10 ± 0.001 *	−1.53 ± 0.001 *	12.52 ± 0.33 *	2.56 ± 0.23 *
Meteorological factors
T (°C)	−0.003 ± 0.000 *	0.61 ± 0.000 *	0.09 ± 0.000 *	−0.47 ± 0.001 *
RH (%)	0.000 ± 0.000 *	−0.39 ± 0.000 *	0.04 ± 0.000 *	−0.18 ± 0.000 *
WS (m/s)	−0.18 ± 0.001 *	17.07 ± 0.000 *	−18.53 ± 0.000 *	−9.90 ± 0.003 *
Specific regressions
R2	0.57	0.58	0.70	0.31
Dep.	0.21	53.57	39.06	16.34

Notes: activity restrictions due to coronavirus, dummy variable (a no restriction 5-y period, years 2015–2019); ¹ the table report coefficients and standard errors for the São Paulo, Los Angeles, New York and Paris network station regressions; the number of regressors in the GLM was 4; ² SE are calculated by bootstrapping (200 samples each); the pollutant and meteorology, clustering by day; in total 186 observations were sampled for each pollutant/city and the sample periods were March 2015–March 2020, including daily averages (Table 2a,b); ³ a, no activity restriction scenario, dummy variable; * analysis of variance p < 0.01; Model OLS (Ordinary least square). Dep. = dependent variable (Total (March 2015–2020)).