A stagnant weather pattern expected to linger through this week has prompted local officials to declare a Stage 1 burn ban in Clark County. The ban takes effect at 5 p.m. today, according to the Southwest Clean Air Agency.A stage one burn ban means the use of all wood fireplaces and uncertified wood stoves is prohibited. (Uncertified wood stoves are generally made before 1990 and lack a certification label on the back.) Outdoor burning is also not allowed during a Stage 1 ban.Homes that rely on wood burning as their only source of heat, however, are exempt from the ban.Unlike summertime burn bans, this week’s announcement isn’t related to fire danger. Instead, officials hope to minimize air pollution as particulates build up in the air.The ban will remain in effect until further notice, according to the clean air agency. A high-pressure system is expected to keep a stagnant air mass in place over the region for at least the next several days. That pattern, combined with poor daytime ventilation and other factors, may cause moderate to high levels of fine particle air pollution, according to the agency. Limiting burning aims to minimize that effect.Updated air quality information is available at Southwest Clean Air Agency.