MICS6814: spikes in sensor readings

I have a MICS6814 3-in-1 Gas Sensor Breakout connected to a Raspberry Pi 4B. I am using the Python library to read the sensors continuously:

import sqlite3
import time

from mics6814 import MICS6814

gas_sensor = MICS6814()

while True:
    epoch = time.time_ns() // 1e9

    oxidising, reducing, ammonia, adc = gas_sensor.read_all()

    con = sqlite3.connect("~/Documents/air-quality.db")
    cur = con.cursor()
        INSERT INTO sensor_readings (Oxidising, Reducing, Ammonia, ADC, Epoch)
        VALUES ({oxidising}, {reducing}, {ammonia}, {adc}, {epoch})""")


The read_all() function takes a few seconds to run, so this loop ends up reading about every 5 seconds.

My problem is that I am seeing plenty of spikes in the data.

Am I doing something wrong?

Could it be faulty hardware?
In other words, could my particular MICS6814 be bad?