Our protocols for environmental and biomarker sampling to address health impacts of household air pollution exposures can be applied in remote and resource-poor field settings among vulnerable populations globally. The techniques are customized for assessing long-term personal exposures for multiple air pollutants instead of relying on proxy indicators on large study populations. Exposure assessment during critical development windows, such as pregnancy and first year of child life, can inform prevention strategies for important health outcomes, such as low birth weight and child pneumonia.
These methods are applicable for air pollution and health effects studies among rural and urban population in many low and middle-income country setting, especially in the context of evaluating the interventions. Training for field and laboratory protocols concerning exposure and biomarker assessments are often not provided in a context-specific manner or reinforced periodically. Investigators must invest adequately in such trainings.
Written standard operating procedures often are not included in study protocol manuscripts. Further, without visual demonstration, investigators often cannot reliably reproduce field study protocols across settings. To begin, check the filters for damages, if any, using a light box and place them in a clean filter keeper in an air conditioned room for 24 hours.
After conditioning, take the filter out and hold it for 10 seconds to deionize it. Then carefully place the filter on the microbalance's weighing tray and record the weight as weight one in the case report form. Then remove the filter and place it back on the filter keeper or a Petri dish.
For personal monitoring, place the instruments in a vest. And for microenvironmental monitoring, place the instruments on mounted metal stands at appropriate locations. After a five-minute walkthrough in the monitoring area, record the start and end time for all the monitoring instruments in the respective case report forms.
On the removal day of samples, wrap the instrument in aluminum foil and place it in a resealable cover for transporting it to the field office. Clean all the Enhanced Children's MicroPEM parts using a 70%isopropanol dipped swab, and launch the sampler using the MicroPEM software. After setting up the calibration assembly, press the start button and wait five minutes for it to stabilize.
Then adjust the flow rate within 5%of 0.3 liters per minute, and record the information in the respective case report form. Next, connect the HEPA filter directly to the Enhanced Children's MicroPEM inlet. Adjust nephelometer offset until the value reads 0.0 and record the reading in the respective case report form as demonstrated earlier.
Set the program to 24 hours in the software, and click the Submit Calibration Values button. Download and save the Enhanced Children's MicroPEM data after recording the post sampling flow rate in the case report form H48. To measure the black carbon in the transmissometer, ensure the cartridges are available in both the blank and sample slots.
Then perform the scan on a neutral density and a blank filter with the assigned ID.Once done with the blank filter scanning, place the lab blank into the sample cartridge slot above the sample diffuser and insert it into the position two slot of the instrument. Then remove the lab blank and continue the scan with test and sample filters. After completing the scans, remove the filter and return it to the filter keeper.
Next, select the scanned data, click Accept and Save. Using the software, start and set up the carbon monoxide data logger to one minute. After sampling, open the data logger, press Stop to disconnect the USB data logger and save the downloaded data.
Next, place the carbon monoxide logger in the calibration box with the inlet vent of the sensors facing toward the air inlet port of the calibration box. Set a flow rate of two liters per minute of zero grade air or room air for five minutes and note the start and end time. Then reduce the airflow to one liter per minute for another five minutes, and again, note the start and end time.
For the time and location logger, connect a charged power bank to ensure that the logger is working. For the time and location monitor, insert a CR 2032 battery into the O Model TLM monitor. Then press the soft cover to hear a click sound and a flashing green light indicating the functioning of the monitor and transmission of the signal.
After sampling, download the data from the boot drive in the loggers SD card to copy and save the files. For stove use monitoring, place the thermocouple probe near the cumbersome zone of the cook stove. Then open the Geocene app, enter the required particulars, and press Start New Mission.
Download the data every two weeks through the app. For ambient monitoring, in a mounted instrument of ambient PM 2.5, set the sampling interval to five minutes from the menu option. After noting the start time, perform flow calibration using a null filter and save the real-time data.
Next, remove the previously installed null filter and place a pre-weighed filter in the clean filter holder. Stop the sampler after 24 hours and save the real-time data. Then place the aluminum foil wrapped filter in a resealable bag for cold chain transport.
Thaw the collected urine samples and aliquot different volumes into different cryovials and store them at minus 20 degrees Celsius until use. For dried blood spots, keep the lancet in a horizontal position at the skin puncture location and prick. After pricking, wipe away the first drop of blood with a sterile cotton gauze.
Then place the collected blood-filled capillary tube immediately within the circle of the protein saver card. For the valid spots, the volume of blood must be sufficient enough and it occupy at least 50%of the spot circle. Allow the specimen to air dry overnight at room temperature and then store it at minus 20 degrees Celsius.
With the help of the environmental monitoring instruments and the data collection procedures described in this study, it is possible to obtain more reliable outcomes. For example, the success rate of collecting valid dried blood spots from mothers of three visits is 100%for baseline, 93%for pregnancy followup one, and 83%for pregnancy followup two. Correlation analysis of the urinary specific gravity measured between the field laboratory and central laboratory showed good agreement.
Besides these technical steps, the participant cooperation reinforced periodically throughout the study which is essential for valid data collection. The procedures described here are applicable only to ECM, Geocene Dots, E-Sampler, and OP-21 BC monitors. While using other monitors, except monitor placement, and filter weighing, we have to follow manufacturer's specification.
This method can be used for next-generation multiple air pollution monitoring devices.
