Established by the South Coast Air Quality Management District (SCAQMD), Rule 1466 is designed to minimize fugitive dust emissions during earth-moving activities at sites containing specific toxic contaminants. Provisions in Rule 1466 cover three main areas – dust control measures, monitoring requirements, and notifications/reporting. Recently, Rule 1466 has undergone a series of amendments, introducing enhanced monitoring requirements and further clarifying definitions under the rule, among other changes. For more background on the origins of Rule 1466, see this blog.

The overall goal of Rule 1466 is to protect communities and sensitive receptors from the harmful effects of toxic air pollution caused by earth-moving activities. By proposing additional clarifications to monitoring, fencing, and stockpiling requirements under the rule, SCAQMD aimed to make it more enforceable and streamlined. Updated monitoring requirements reflect recent advancements in instrumentation technology, allowing for PM₁₀ monitoring to take place on a continuous, real-time basis. To further protect communities, dust control requirements have been extended to include sites adjacent to schools. Below, we have outlined some of the key changes site managers, developers, and air quality professionals will need to be across. For a complete account of Rule 1466 amendments, check out this brief.

Updated stockpiling requirements include daily inspections of stockpiles (including non-working days). The new rule calls for increased stabilization or covering of stockpiles during periods of inactivity where ambient monitoring is still occurring, such as lunch breaks. An exclusion has also been added where some sites will no longer need additional fencing should a physical barrier (e.g., a wall, storage containers) exist that meets all height requirements.

SCAQMD has further updated instrumentation approval requirements as part of these amendments. Under the new rule, PM₁₀ monitoring systems must be capable of logging data every 1 minute or less (down from the current limit of 10 minutes.) Operators must now calculate dust concentration using a rolling average, starting when earth-moving activities commence (a shift from the current 2-hour average, calculated at the top of each hour.) All systems must also include a heated sampler inlet to cut down on humidity interference. In addition, operators may now re-designate and move monitors if seasonal wind direction changes by more than 90 degrees.

Site managers should be aware that Rule 1466 now includes additional notification requirements, including a project completion date and the inclusion of wind direction and speed data for exceedance notifications. Under these amendments, SCAQMD has removed the article that previously allowed site operators to request alternative provisions for PM₁₀ limits, monitoring methods, calculations, or other measures. This helps clarify the rule and clearly define expectations for maintaining regulatory compliance.

The Aeroqual Dust Sentry PM10 monitor is one of only a few pre-approved monitors listed for use under Rule 1466 by SCAQMD. By using a Rule 1466-approved monitor, you’ll save the time, money, and hassle of worrying whether your monitoring system meets the necessary reporting and measurement requirements on your next construction or remediation project.

Set automatic real-time alerts in line with Rule 1466 using Aeroqual Site Contribution, our intelligent remediation monitoring software. Aeroqual Site Contribution features in-built selectable air quality regulations, simply select the regulation you need and let the software do the rest.

If you’d like to learn more about complying with Rule 1466, check out this free webinar, and don’t hesitate to get in touch!