VEVOR Air Quality Monitor 9-IN-1, CO2, Temperature, Humidity, Formaldehyde TVOC AQI Tester, Professional PM2.5 PM10 PM1.0 Particle Counter for Indoor/Outdoor, Air Quality Meter w/Alarm Thresholds

I did not find any information about calibration requirements or frequency in the product description or customer reviews.

According to the product description, the CO2 readings are accurate within ±10%. Customers find it fairly accurate when compared to other devices.

This can not monitor carbon monoxide.

Cannot be modified manually You cannot modify the alarm thresholds. If this answer does not resolve your issue, please contact us again for assistance.

While customer reviews don't specifically mention visibility in bright sunlight, they generally appreciate the product's display. One review mentions the device's accuracy when compared to other temperature and humidity monitors.