Meteorological Influences on Seasonal Variation of Fine Particulate Matter in Cities over Southern Ontario, Canada

Table 3

Comparison of mean hourly meteorological conditions at the surface (temperature, humidity, surface pressure, and wind speeds) for both clear (PM_2.5 ≤ 5 𝜇g/m³) and polluted (PM_2.5 ≥ 30 𝜇g/m³) times at cities in southern Ontario. The cities are ordered by descending latitude (see Table 1 and Figure 1(a)).

City	PM2.5 range	PM2.5	Temperature	Relative humidity	Pressure	Wind speed	Number of hours
	(𝜇g/m^3)	(𝜇g/m^3)	(°C)	(%)	(hPa)	(km/h)
Thunder Bay	0–5	2.5	17.7	68.4	992.2	12.0	1222
	30–55	36.4	17.5	80.1	990.2	6.9	19
Sault Ste. Marie	0–5	2.6	16.6	67.9	994.3	10.8	1161
	30–55	35.3	19.6	69.9	991.0	6.9	30
Sudbury	0–5	6.4	18.3	69.1	974.3	11.9	2165
	30–55	33.0	25.8	63.3	971.4	16.8	10
North Bay	0–5	2.3	16.3	71.4	972.3	11.7	1223
	30–55	32.4	22.5	73.0	968.9	12.5	19
Barrie	0–5	2.7	17.0	71.2	978.0	11.6	921
	30–55	34.9	22.8	76.2	977.4	9.4	54
Toronto	0–5	3.0	19.1	64.4	995.8	18.2	623
	30–55	35.8	24.0	75.8	991.4	14.3	110
Hamilton	0–5	2.7	18.1	72.1	988.6	13.6	735
	30–55	35.2	22.8	78.6	984.8	15.0	128
London	0–5	2.9	18.4	69.1	984.4	11.2	727
	30–55	33.0	22.3	81.0	979.7	11.0	97
Sarnia	0–5	4.0	17.6	73.6	989.1	18.4	317
	30–55	37.3	24.1	75.6	991.7	12.0	204
Windsor	0–5	3.0	20.4	63.4	994.8	14.0	485
	30–55	35.1	24.9	71.9	991.6	12.6	156