Characteristics of the particle number concentration during the heating period in Harbin

The characteristics of the atmospheric particle number concentration were studied during the early heating period. The data of PM2.5, relative humidity, temperature, wind scale, and atmospheric visibility were obtained in meteorological monitoring performed online. The results show that, the number of the days, of which the visibility was less than 10 km, was 3, 11, and 9, respectively. The days on which the PM2.5 concentrations were higher than 100 mu g/m(3) were 1, 9, and 9 in October, November, and December respectively. The average of the particle number concentration were 17775, 36345, and 34640, respectively; the average of visibility were 23.6, 8.5, and 9.7 km, it shows that an increase in the number concentration is mainly caused by coal-burning heating in November and December. The range of number concentration has a large fluctuation in December. One part of particles was adsorption in the snow, thereby falling to the ground, so that the content of the suspended particulate matter in air is reduced. The particle number concentration was significantly correlated with PM2.5 concentration, visibility, and relative humidity. This shows that the number concentration of PM2.5 in the atmosphere is higher and the visibility is lower.