Gaseous elemental mercury emissions from informal E-Waste recycling facilities in Pakistan

[Display omitted] •Measurement of GEM emissions from urban atmosphere in Pakistan.•Open burning, and physical dismantling are common e-waste recycling practices.•E-waste sites from Karachi, Lahore, and Peshawar were found highly contaminated.•Lower seasonal variations indicating the stable emission sources throughout year.•Workers and public living close to these facilities are exposed to hazards of GEM. Detrimental effects of mercury (Hg) on ecosystems and human health have been well-documented. Whereas emissions of gaseous elemental mercury (GEM) from e-waste recycling have been reported in developed countries, much less is known about the situation in the Global South. Using a total of 132 passive air samplers, seasonally resolved concentrations of GEM in air were measured continuously at 32 informal e-waste recycling facilities and background location in Pakistan for a period of one year between September 2020 and December 2021. Annual average GEM concentrations at the studied locations ranged from 1.8 to 92 ng m−3. Among the studied cities, higher concentrations were measured in Karachi (mean ± s.d: 17 ± 22, range: 4.2–92 ng m−3), Lahore (16 ± 4.2, 8.2–22 ng m−3) and Peshawar (15 ± 17, 4.9–80 ng m−3), while lower levels were measured in Hyderabad (6.9 ± 6.2, 3.1–25 ng m−3), consistent with a higher rate of informal recycling activities in metropolitan areas. Seasonally, higher GEM levels occurred during autumn (15 ± 16: 3.3–92 ng m−3) and summer (13 ± 8.7: 1.8–80 ng m−3) than in winter (12 ± 8.4: 2.5–49 ng m−3) and spring (9.2 ± 7.3: 1.8–80 ng m−3), possibly reflecting enhanced volatilization at higher temperatures and/or varying magnitude of recycling operations in different seasons. Policies and strict regulations related to e-waste management should be developed and implemented urgently in the country.